This invention relates generally to medical (including veterinary) catheters and, more particularly, to a unique medical catheter designed to be removably anchored within a body cavity by forming and maintaining an obstruction to removal in the form of a restraining portion in the distal end of the catheter until it is desired to withdraw the catheter from the cavity.
Flexible catheters are widely used for percutaneous drainage of fluid collections and percutaneous nephrostomy. They are also used for drainage of abscesses, cysts, pleural effusions, empyemas, and other mediastinal collections. In such applications, the catheters are typically inserted either over a previously emplaced guide wire or by direct puncture using a trocar stylet.
Once in position in a body cavity, it is desirable to anchor the catheter before drainage begins. This may be done by forming a restraining portion in the distal end of the catheter in the form of a pigtail, a J-curve or a malecot rib. In order to reliably anchor and then later easily remove the catheter, it is important to be able to lock and unlock the restraining portion in the distal end of the catheter from the proximal end of the catheter, where it protrudes from the body.
One technique for locking a pigtail in the distal end of a drainage catheter is described in U.S. Pat. No. 4,740,195 to Lanciano. That patent describes a suture attached to the distal end of the catheter which is held in position in a stopcock-type of locking mechanism in its proximal end. Another prior art device for locking a pigtail in the distal end of a drainage catheter with a suture arrangement uses a latex sleeve to cover the suture as it exits from a hole the wall of the catheter at its proximal end to thereby holds it in place and also reduce leakage. Both of these prior art techniques are unsatisfactory since they permit liquid leakage along the suture as it emerges from the catheter and gas leakage at the hole in the wall of the catheter.